Laser arseneto de gálio em tendão calcâneo de ratos: avaliação da resistência mecânica à tração

Low intensity lasertherapy has been used to accelerate tissue healing, therefore decreasing rehabilitation time and morbidity leading to a better and complete functional performance. The purpose of this study was to assess the ultimate load of calcaneus tendon in a traction model. Twenty five adult wistar rats were submitted to GaAs laser device once a day. Twenty adult animals were submitted to tenotomy of the calcaneus tendos followed by suture of the experimentation site and divided into two groups: group A (right limb - suture and lasertherapy) and group B (left limb - suture and simulation). These two groups sere divided into two subgroups. The eighth day postoperative subgroup A1 – B1 and the fifteenth day postoperative subgroup A2 – B2. The remaining five animals in the C group (control group with no treatment). Lasertherapy has started 24 hours after the surgical procedure with a 4J/cm2 dose. Tendons were dissected and the ultimate load were assessed with a EMIC™ universal testing machine. Statistically difference (p=0,04) were found in the 8th day lasertherapy treatment group. The control group strenght values were very similar to the tendons treated with laser. According to the rupture site frequency, musculotendinous region occured as high as 77% in the A1 and suture region 66% in the B1. Musculotendinous ruptures occured in 90% and 80% in the groups A2 and B2 , respectively. The Laser GaAs (904nm) daily dose of 4J/cm2 increased the rat calcaneous tendon strength.